The technology relates to scalable testing of complex networks and/or complex network devices. Network test equipment to perform such useful scalable testing should emulate a large number and variety of network devices without artificial limits on the overall topology, configuration, and types of traffic.
Traffic types vary by supported network layer, link layer, and physical layer protocols, such as Internet Protocol, Generic Routing Encapsulation, Ethernet, Virtual Local Area Network 802.1q, Multiprotocol Label Switching, Point to Point Protocol over Ethernet, Point to Point Protocol, and Layer 2 Tunneling Protocol, WiMAX, Provider Backbone Bridge 802.1ah, and Asynchronous Transfer Mode. Existing network test equipment places artificial limits on the types of emulated traffic, in particular variable combinations of network layer, link layer, and physical layer protocols.
For example, an earlier TestCenter™ product from Spirent Communications, Inc. emulated only a limited number of fixed combinations of network layer, link layer, and physical layer protocols. These combinations were coded in such a way that the upper layers were aware of the lower layers, and therefore fail to take advantage of layering abstraction. The expected improvements to such a product would preserve the already existing support for the limited number of fixed combinations of network layer, link layer, and physical layer protocols, and gradually supplement this limited support with an additional number of fixed combinations of network layer, link layer, and physical layer protocols, perhaps as technological progress resulted in new network layer, link layer, and physical layer protocols.
In another, especially limited example, Internet Protocol aliasing adds multiple Internet Protocol addresses to a network interface; this example is especially limited because it covers only the single fixed combination of Internet Protocol and Ethernet.
Support for emulating an arbitrarily variable number of combinations of network layer, link layer, and physical layer protocols would be unexpected, because of the significant investment sunk into already existing support for emulating the limited number of fixed combinations of network layer, link layer, and physical layer protocols, and the collectively prohibitive cost of adding incremental support specific to emulating each and every possible combination of network layer, link layer, and physical layer protocols.